Conventionally, the electromagnetic shock wave lithotripter has types of shock wave sources: one is the incident focusing configuration, called self-focusing one, as shown in FIG. 4 and one of the others is the sound lens focusing configuration as shown in FIG. 5. The operation principle of the electromagnetic shock wave generator is as follows. When a strong pulse current passes through a coil, an induced current will be generated in a metal diaphragm. These two currents then form magnetic fields that repel each other, resulting in a sudden and short movement of the metal diaphragm. Consequently, a strong pressure pulse is generated in the nearby water. The pulse is gradually reinforced in propagation and thereby forms a shock wave.
With the incident focusing configuration shown in FIG. 4, the concave spherical coil will result in a concave spherical shock wave, which travels stably and keeps on focusing in propagation, therefore, without the need of the sound lens. With the sound lens-focusing configuration shown in FIG. 5, the planar coil will generate a planar shock wave. Therefore, the sound lens is required to focus the wave. In one stone fragmentation session, it is necessary to perform the high voltage pulse discharging for hundreds, or even thousands of times in order to disintegrate stone in the human body completely. Thus, a great amount of heat is produced in the coil. If the heat is not dissipated immediately, the metal diaphragm will be softened, destabilized and crumpled, thus the coil will be overheated and destroyed. Meanwhile, the interaction between the shock wave and the water will also result in cavitation and thus form bubbles in the water. The bubbles will adhere to the metal diaphragm, making the heat dissipation even worse. Further, when bubbles collapse under the interaction with the shock wave, micro-jets that can damage the metal diaphragm will be formed. Therefore, the conventional electromagnetic shock wave generator has a short working life, and it is necessary to replace the metal diaphragm very often. Accordingly, the configuration shown in FIG. 5 is often used in the prior art, wherein a metal diaphragm is placed over the coil, thereby the shock wave produced goes upward. In this way, the bubbles adhering to the metal diaphragm will moves upward under the action of the buoyancy force, and at the same time the heated water will also rise continuously, thus forming a fluid circulation in the chamber body. However, because the whole shock wave source is located in the lower part, it is inconvenient for physicians to move or locate it during treatment.
Therefore, it is an object of the invention to provide a vortex bubble-removing and cooling system for the electromagnetic shock wave generator for the lithotripter, which is capable of removing the bubbles adhering to a metal diaphragm automatically and dissipating the heat generated in the metal diaphragm immediately.